Demulsifying agents break emulsions and/or mixtures of polar solutes like water, and non-polar solvents like oil. They are used in functional fluids (such as, but not limited to, metal removal fluids, greases, rust and oxidation fluids, hydraulic oils, compressor oils, fuels and transformer fluids) to inhibit formation of emulsions, break emulsions that have developed, and to inhibit corrosion.
Emulsions and mixtures can be separated by various means including mechanical, thermal, and chemical. The mechanical separation of mixtures can generally result in the at least partial separation of aqueous and/or oil phases that may be present in the mixture, but when these phases are present in the form of an emulsion, mechanical separation often fails to provide a desirable degree of separation. Various chemical means have been provided for separation of emulsified phase mixtures, but various industries require still further levels of separation that here to fore have not been adequately provided by conventional chemical means.
Among their industrial uses, demulsifiers are commonly used to dehydrate and desalt crude oil during extraction or refinement. Typically, during production of crude oil, water gets emulsified to it to give a water-in-oil emulsion. This water-in-oil emulsion gives rise to several down stream problems; corrosion during refinery processes and greater energy requirement to pump the more viscous emulsion are to name a few. Thus, demulsifiers are extensively used in oil field applications to break water in crude oil emulsions.
Other industrial uses include hydraulic systems wherein the demulsifiers must be effective at high temperatures, often in excess of 300° C. Failure of a demulsifier in a hydraulic system may lead to catastrophic failure. Demulsifiers are also frequently put to use in hydraulic systems to prevent corrosion. In the presumed mechanism of corrosion inhibition, the demulsifier adsorbs on the metal surface forming a protective film against polar solutes.
Demulsifiers are known in the art and usually comprise blends of surface active chemicals and the spectrum of usable compounds has been expanded particularly due to the introduction of specific organic silicone compounds for breaking petroleum emulsions. However, despite the large number of demulsifiers available on the market, it is not possible to break all of the occurring petroleum/water emulsions rapidly, safely, efficiently, and with small quantities of addition products.
There remains a need for demulsifiers capable of breaking and/or separating such emulsions more effectively.